Timeline

Ridley gave this rather terse description, published in July 1905 of a large crypt ("the biggest species I have seen except for C. ciliata") from Sarawak. The flower was "yellow and purple":

The Aroids of Borneo
H. N. Ridley
Journal of the Straits Branch of the Royal Asiatic Society
No. 44 (JULY 1905), pp. 169-188
Published by: Malaysian Branch of the Royal Asiatic Society
Article Stable URL: http://www.jstor.org/stable/41561024

Comments: Does CIL get over a foot? I've seen some big ones but I haven't seen one 18 inches, so the biggest Crypt Ridley saw may be around a foot, that is the biggest crypt Ridley had seen was half the size of the largest ones found in aquaria today. Besides, this is a plant from Sarawak, our plant is from far way in Kalimantan; Borneo is a big place!

So, I'd feel pretty confident that it's cordata and not a hybrid and that the plant has been known from at least 2 sources in aquaria from a place known to have the plant still there. In theory, C. cordata grabowski is the Borneo form of the COR complex, C. cordata cordata with the same solid yellow flower as this is only found in peninsular Malaysia and is a much smaller plant than this, as is C. cordata grabowski and there is little question now, that cordata cordata also grows in Borneo (although it would be nice to see flowers of those wild plants to confirm this, but it's not like there's any other two foot tall red crypts we know of anywhere) I'd like to see the karyotype, grabowski is unique in that it's diploid, n=68 wheras cordata is n=34.Floating a piece of the rhizome until roots form and taking a small section with root hairs and some lucky goes with a fixative and a stain or two might yield a slide or two in mitosis and if the chromosomes are visible at high magnification you're either going to see 34 or 68 of them. I'm betting on 34 myself. Any other numbers and we'll have to think about it, but for now I'd hazard a guess and say it's a distinct cordata morphospecies and should either be considered a cultivar or proper subspecies of C. cordata, depending on an inventory of (what's left of) the rest of the Island. The name "grandis" has been loosely attached to this plant for over 60 years and barring any technical reason against, seems the most prudent. DNA analysis would also shed more light on the matter of course. I'm fairly confident I can get a sample from Canada of the plant maintained there for analysis if anybody has the capability to do that, if not I can poke around and find somebody who can. http://crypts.home.xs4all.nl/Cryptocoryne/Gallery/cor/cor-group.html http://crypts.home.xs4all.nl/Cryptocoryne/Gallery/cor/cor-group.html Ridley described grandis in The Aroids of Borneo H. N. Ridley Journal of the Straits Branch of the Royal Asiatic Society No. 44 (JULY 1905), pp. 169-188 Published by: Malaysian Branch of the Royal Asiatic Society Article Stable URL: http://www.jstor.org/stable/41561024